A player traded will affect your team the following year. If you sign a player to a three year contract with a signing bonus of 1.5 million, he plays a year, and he has two years left on his contract when you trade him, then the following year, your cap penalty is 1 million(500K+500K. Add up the the total of signing bonus for all remaining years of the contract.
If you give a player a new contract who already is under contract, you will still be stuck with the cap penalty. However, if you sign a player who is unsigned, and don't give him a signing bonus, you will not be charged with a cap penalty.
If you think you may trade a player, don't give him a signing bonus, or make it minimal, but if you plan on keeping him for several years, give him the highest bonus possible.

If you want, you can clear all cap penalties. (At least on Madden 05) Go to My Team in franchise. On the Xbox, press Y. The penalties will clear._________________It feels great to live in the heart of Big Blue Nation. And I don't mean Duke

if you start out a season with high cap penalties and dont have eough players itll clear your cap penalties and reduce your morale a bit_________________When your done playin' football, go play football